Electric feeder rail construction

ABSTRACT

A feeder rail construction for rail-type electrification systems comprising an elongate, extruded aluminum support member of good conductivity, having a pair of coextensive spaced-apart parallel longitudinal slots, and an elongate wear-resistant channel member preferably of stainless steel, carried by and coextensive with the support member and characterized by a U-shaped cross section formed by a pair of flange portions and a connecting web portion. The edges of the flange portions are turned back upon themselves so as to present thickened rims. The walls of the slots of the support member have a ribbed configuration constituting irregular surfaces, and the channel member flanges are press-fitted into the slots so as to be permanently retained therein. During the press-fitting operation, the irregular surfaces of the slot walls are sheared or scraped clean, thus exposing a fresh aluminum surface free of oxide which provides improved electrical conductivity between the two members. At least one wall of each support member slot is swaged against the thickened rim of the flange so as to tightly engage the latter and permanently retain the channel member.

United States Patent 1191 Howell, Jr.

[ Sept. 2, 1975 1 ELECTRIC FEEDER RAIL CONSTRUCTION [76] Inventor: Alleyne C. Howell, Jr., 470 Surf Ave., Stratford, Conn. 06497 [22] Filed: Oct. 5, 1973 [21] Appl. No.: 403,939

[52] US. Cl. 191/29; 191/32; 238/143 [51] Int. Cl. 1360M 1/30 [58] Field of Search 191/29, 22, 23, 32, 45, 191/49; 238/134, 143-148 [56] References Cited UNITED STATES PATENTS 1,042,545 10 1912 Gamwell 238/143 3,566,048 2/1971 Martin 191/32 Primary Examiner-M. Henson Wood, Jr. Assistant ExaminerRichard A. Bertsch Attorney, Agent, or Firm-11. Gibner Lehmann; K. Gibner Lehmann [57] ABSTRACT A feeder rail construction for rail-type electrification systems comprising an elongate, extruded aluminum support member of good conductivity, having a pair of coextensive spaced-apart parallel longitudinal slots, and an elongate wear-resistant channel member preferably of stainless steel, carried by and coextensive with the support member and characterized by a U- shaped cross section formed by a pair of flange portions and a connecting web portion. The edges of the flange portions are turned back upon themselves so as to present thickened rims. The walls of the slots of the support member have a ribbed configuration constituting irregular surfaces, and the channel member flanges are press-fitted into the slots so as to be permanently retained therein. During the press-fitting operation, the irregular surfaces of the slot walls are sheared or scraped clean, thus exposing a fresh aluminum surface free of oxide which provides improved electrical conductivity between the two members. At least one wall of each support member slot is swaged against the thickened rim of the flange so as to tightly engage the latter and permanently retain the channel member.

8 Claims, 7 Drawing Figures PATENTEDSEP 21% V 3.902579 snwlqfz ill i i ELECTRIC FEEDER RAIL CONSTRUETION BAC KGROUND This invention relates generally to rail electrification systems and more particularly to feed rails made up of separate components of dissimilar metals which are joined together, one of the metals being a relatively good conductor such as copper or aluminum, and the other having surface characteristics which resist galling and pitting, thus making it more adaptable for use with sliding contact shoes and the like. In the past, some conductor rails have been constituted entirely of either copper or aluminum. The use of copper is generally considered to be too costly. On the other hand, aluminum is less expensive but is soft and has a tendency to gall easily when it is used as a sliding Contact; also, it has a lower conductivity than that of copper. Efforts to plate the aluminum with another metal have been made and have met with moderate success, except that even heavy plating will wear off after extended use of the rail. Where a contact component of a dissimilar metal was fastened to the main conductor portion of the rail, problems were encountered with looseness and poor electrical conductivity between the two metals. In addition, where one of the metals was aluminum an oxide would form on its surface, which tended to insulate the contact metal or component from the conductor component. Also, the different metals had dissimilar coefficients of thermal expansion. which led to abnormal stresses being developed within the rail itself under temperature extremes. This caused unsatisfactory operation in many of the constructions heretofore proposed.

SUMMARY The above disadvantages and drawbacks of prior feeder rail constructions are obviated by the present invention, which has for its object the provision of a novel and improved electric rail which is simple and inexpensive in construction, and especially reliable in operation over prolonged periods of use. A related object is the provision of a rail construction as above, which has the combined advantages of good electrical conductivity and freedom from contact degradation due to pitting and galling, while at the same time being characterized by relatively inexpensive material and fabrication costs.

The above objects are accomplished by a rail construction comprising an elongate extruded aluminum support member having a pair of substantially parallel, coextensive longitudinal slots, combined in a unique manner with a stainless steel contactor or channel member comprising oppositely disposed flange portions and a connecting web contactor portion. The edges of each of the flange portions are turned back upon themselves to present thickened rims which are press-fitted into the slots in the support member. The support member slots have roughened walls such that during the pressfitting operation some of the wall material is sheared, or scraped, providing an oxide-free surface for making good electrical contact with the contactor flanges. At least one wall of each of the slots is swagcd against the adjacent flange edge to thereby permanently retain the channel or contactor member to the support member.

In another embodiment of the invention a pair of Conductor rails as herein constructed, having ends adapted to abut one another are mechanically and electrically joined by a elongate, metal connector block provided with a plurality of transverse holes in the ends of the rails. Metal (aluminum) plugs are press-fitted into the holes and thus permanently fasten the rail ends together by means of an all-metal joint.

Other features and advantages will hereinafter appear.

In the drawings illustrating several embodiments of the invention:

FIG. 1 is a side elevational view of a rail electrification system employing the improved rail construction of the present invention, shown engaged by a sliding conductor shoe.

FIG. 2 is a section taken on line 2-2 of FIG. 1.

FIG. 3 is a view like that of FIG. 2, of the support member component of the rail construction, constituted in the form of a metal extrusion; the shape shown is before its assembly to the channel or conductor part of the rail.

FIG. 4 is a side elevational view of a mechanical and electrical joint in the form of an elongate conductor block for fastening together abutting ends of adjoining rail sections, the joint constituting another embodiment of the invention.

FIG. 5 is a top plan view of the conductor block part of FIG. 4.

FIG. 6 is a section taken on line 6-6 of FIG. 4.

FIG. 7 is a section taken on line 77 of FIG. 6.

Referring first to FIG. 1 there is illustrated a rail-type electrification system generally designated by the numeral 10, comprising a conductor rail assemblage l2 and a sliding contact shoe assemblage 14, the latter including a body portion 16 having slots 18, 20 by which it can be swivel-mounted on a trolley or carriage (not shown), and a contact 22 having an expansive contact surface 24. A lead 26 electrically connected to the contact 22 is shown extending away therefrom for connection to a hoist motor or other equipment (not shown) to be energized from the rail. As seen in FIG. 1, the rail assemblage is supported from a beam 28 by plastic or glass insulators 30 having threaded bores and screws 32 received therein.

Referring now to FIGS. 1 and 2 and in accordance with the present invention there is provided a novel and improved rail construction 12 comprising an elongate, electrically conducting support member or rail 34 having a pair of coextensive, substantially parallel, l0ngitu dinal slots 36, 38 and an elongate, electricallyconducting channel member or channel 40 constituting an antipittins, anti-galling contactor member, having a pair of flange portions antipitting, 44 together with a connecting web portion 46. The flange and web portions define a generally U-shaped crosssectional configuration. The support member 34 is shown in FIG. 3 before assembly of the channel member thereto. As shown, the opposite walls of each of the slots 36, 38 have a rough. irregular surface configuration in the form of small, longitudinal ribs 48, and 52, 54 which run lengthwise with the slots.

Referring again to FIG. 2 it can be seen that the edges or end portions 56, 58 of the channel member flanges 42, 44 are turned back upon themselves to provide a thickened rim area or cross section. During the assembly ofthe two pieces, the thick rims of the flanges of the channel member 40 are press-fitted into the slots 36, 38 of the support member 34. By comparison of FIGS. 2

and 3 it can be seen that as this is done, the ribs 48, 50 and 52, 54 in the slot walls are scraped and somewhat sheared.

It has been found that aluminum provides a satisfactory material for the support member 34, representing a good compromise between electrical conductivity, weight, and cost. Stainless steel has been found to be a desirable material for the channel member, since there is little tendency to gall or become pitted, as compared with pure aluminum or aluminum alloy. By the present invention, during the press-fitting of the member 40 to the member 34 the shearing of the aluminum ribs on the slot walls removes or scrapes the aluminum oxide coating therefrom and momentarily exposes an unoxidized aluminum surface, this greatly improving the electrical contact between the support member and channel member. An anti-oxidant compound is applied to the slots prior to the press-fitting operation, further enhancing the conductivity which results. Also, the wall surfaces of the slots remain sealed to a certain degree after the assembly, thus further preventing reoxidizing of the aluminum. Optionally, the antioxidizing grease can be sprayed on the walls immediately prior to assembly, in order to most fully inhibit the oxide formations thereon.

Following the press-fitting operation, the edges 60, 62 adjoining the outer walls of the slots 36, 38 are swaged against the rims of the flanges 42, 44 as illustrated in FIG. 2. This can be done by a suitable machine tool as shown in dotted lines and designated 64. The mouth areas 61, 63 of the slots 36, 38, respectively are thus seen to be narrower than the bottom areas thereof. By such an arrangement the channel member 40 is tightly retained by the support member 34 and remains in excellent electrical contact therewith at a multiplicity of points along their entire common lengths. This is important, since currents on the order of 200-600 amperes are carried by these rails, and poor contacts can cause excessive voltage drops and excessive heating thereof.

As shown in FIG. 2, the web 46 of the stainless steel channel member 40 has a broad surface in contact with the flat surface 66 of the support member 34, thus providing efficient heat transfer from the stainless steel channel member (of poor thermal conductivity) to the aluminum support member (of substantially better thermal conductivity). Expansion and contraction of one member with respect to the other resulting from differing thermal coefficients of the two metals has been found not to cause any malfunction; this construction is thus seen to have a number of distinct advantages.

The support member 34 is shown as also having a channel-like configuration, comprising upstanding, opposite, co-extensive walls 68, 70 with a bottom connecting web 72, and inwardly extending flanges 74, 76 on the upward edges of the walls 68, 70 respectively. The flanges 74, 76 engage a hanger member 78 having a T-configuration, the latter being suspended from the insulator 30 by a bolt 32. The hanger member 78 is capable of sliding movement along the support member, and thus the positions of the insulators 30 along the length of the rail can be adjusted to convenient locations.

Another embodiment of the invention is illustrated in FIGS. 4-7, showing two elongate, metal conductor rail members 80, 82 substantially identical to one another,

having their adjoining end portions 84, 86 adjacent and in abutting relation. Each end portion has a series of transverse fastening holes 88, 90, respectively, extending through the connecting web portions designated 92 and 92a of the support members 94, 94a respectively, but not through the webs 96, 96a of the channel members 98, 98a respectively, (see FIG. 6). With the exception of the transverse holes 88, 90, the rail members 80, 82 are similar in construction to the rail 12 of FIG. 1.

In accordance with the present invention there is provided an elongate connector block 100 disposed alongside and engaging longitudinal surfaces 102, 104 of the abutting rail end portions. The block 100 and support members 94, 94a are all preferably constituted of aluminum. The block has spaced-apart transverse holes 106 substantially in alignment with the transverse fastening holes 88, of the rails. In addition, a plurality of solid aluminum plugs 108 are force-fitted into the aligned holes of the rails and block so as to form a permanent electrical and mechanical connection or joint therebetween. As shown particularly in FIG. 6, the plugs 108 extend through the web 922 of the support member 9411, and are in abutting relation with respect to the stainless steel channel members. The same is true of plugs 108 and the web 92 of support member 94. The above arrangement has been found to provide a very satisfactory joint since, during insertion, the aluminum plugs tend to shear or scrape not only the inner surfaces of the holes in the conductor block but also their own exterior surfaces. This has the effect of removing the (insulating) layer of aluminum oxide and exposing a pure aluminum surface, thus providing a good electrical contact between each of the rails and the block. An anti-oxidizing grease can optionally be applied to the plugs before insertion to inhibit formation of oxide after assembly.

Referring again to FIGS. 2, 3 and to FIG. 1, the present invention also embraces, in a rail-type electrification system, the method of constructing a conductor rail from an elongate support member 34 having parallel, longitudinal slots 36, 38, and an elongate channel member 40 having a pair of flange portions 42, 44 with connecting web portions 46, comprising the steps of folding each of the edges of the flange portions back upon itself so as to present a thickened edge configuration, press fitting the thickened edges of the channel flanges into the longitudinal slots of the support member, and swaging one of the walls of each slot so as to tightly engage the flanges of the channel member and to permanently retain the latter.

From the above it can be seen that I have provided a novel and improved rail construction and fabricating method therefor, and an electrical and mechanical rail joint for rail-type electrification systems, both of said structures and the method being extremely simple and providing highly satisfactory operation and performance, The invention effectively overcomes the problems of poor electrical contact between adjoining rail sections, and provides a satisfactory solution to the galling and pitting of sliding contacts without sacrifice of electrical conductivity. The invention is thus seen to represent a distinct advance and improvement in conductor-rail technology.

Variations and modifications are possible without departing from the spirit of the invention.

I claim:

l. A rail construction for rail-type electrification systems, comprising in combination:

a. an elongate, electrically conducting rail having a pair of coextensive longitudinal slots substantially parallel to one another,

b. an elongate, electrically conducting channel constituting an anti-pitting, anti-galling contactor member having a pair of flange portions and a connecting web portion, said portions defining a generally U-shaped cross sectional configuration,

c. said flange portions of the channel member being pressfitted into said slots so as to permanently retain the channel member on the rail,

d. said slots having outer reentrant walls extending inwardly toward each other, whereby the slots are narrower at their mouth areas than at their bottom areas.

2. The invention as set forth in claim 1, wherein:

a. the flange portions of the channel member each have thickened rims.

3. A rail construction for rail-type electrification systems, comprising in combination:

a. an elongate, electrically conducting rail having a pair of coextensive longitudinal slots substantially parallel to one another,

b. an elongate, electrically conducting channel member having a pair of flange portions and a connecting web portion, said portions defining a generally U-shaped cross sectional configuration,

c. said flange portions of the channel member being pressfitted into said slots so as to permanently retain the channel member on the rail,

d, said slots having outer reentrant walls extending inwardly toward each other. whereby the slots are narrower at their mouth areas than at their bottom areas,

e, the walls of the longitudinal slots having a rough, irregular surface configuration adapted to be scraped clean when the channel member is press fitted into the slots.

4. The invention as set forth in claim 3, wherein:

a. the walls of the longitudinal slots have a ribbed configuration, constituting said irregular surface. 5. A rail construction for rail-type electrification systems, comprising in combination:

a. an elongate, electrically conducting rail constituted as a rigid metal extrusion of channel-like cross section provided with a pair of upstanding opposite, coextensive walls and a bottom connecting web,

b. the upper edges of said walls having inwardly extending flanges,

c. said connecting web having a pair of longitudinal slots opening at the bottom surface thereof,

d, the opposite walls of said slots having irregular surfaces adapted to be scraped clean when the flanges of a channel member are pressed into the slots,

5 6. The invention as defined in claim 5, wherein:

a. the opposite walls of said slots have a ribbed configuration, constituting said irregular surfaces,

7. A rail construction for rail-type electrification systems, comprising in combination:

a. an elongate, electrically conducting rail having a pair of coextensive longitudinal slots substantially parallel to one another,

b. an elongate, electrically conducting channel member having a pair of flange portions and a connect ing web portion, said portions defining a generally U-shaped cross sectional configuration,

c. said flange portions of the channel member being pressfitted into said slots so as to permanently retain the channel member on the rail,

(1. said slots having outer reentrant walls extending inwardly toward each other, whereby the slots are narrower at their mouth areas than at their bottom areas,

e. the flange portions of the channel member each having thickened rims,

f. each of the edges of the flange portions being turned back upon itself, the turnedback edges constituting the said thickened rims.

8. A rail construction for rai.ltype electrification systems, comprising in combination:

a. an elongate, electrically conducting rail having a pair or coextensive longitudinal slots substantially parallel to one another,

b. an elongate, electrically conducting channel member having a pair of flange portions and a connecting web portion, said portions defining a generally U-shaped cross sectional configuration,

c. said flange portions of the channel member being pressfitted into said slots so as to permanently retain the channel member on the rail,

d. said slots having outer reentrant walls extending inwardly toward each other, whereby the slots are narrower at their mouth areas than at their bottom areas,

e. said rail having a channel-like configuration, com prising a pair of upstanding, opposite, coextensive walls and a bottom connecting web, the upward edges of said walls having inwardly extending flanges,

g. said slots being disposed in the bottom surface of said web. 

1. A rail construction for rail-type electrification systems, comprising in combination: a. an elongate, electrically conducting rail having a pair of coextensive longitudinal slots substantially parallel to one another, b. an elongate, electrically conducting channel constituting an anti-pitting, anti-galling contactor member having a pair of flange portions and a connecting web portion, said portions defining a generally U-shaped cross sectional configuration, c. said flange portions of the channel member being pressfitted into said slots so as to permanently retain the channel member on the rail, d. said slots having outer reentrant walls extending inwardly toward each other, whereby the slots are narrower at their mouth areas than at their bottom areas.
 2. The invention as set forth in claim 1, wherein: a. the flange portions of the channel member each hAve thickened rims.
 3. A rail construction for rail-type electrification systems, comprising in combination: a. an elongate, electrically conducting rail having a pair of coextensive longitudinal slots substantially parallel to one another, b. an elongate, electrically conducting channel member having a pair of flange portions and a connecting web portion, said portions defining a generally U-shaped cross sectional configuration, c. said flange portions of the channel member being pressfitted into said slots so as to permanently retain the channel member on the rail, d. said slots having outer reentrant walls extending inwardly toward each other, whereby the slots are narrower at their mouth areas than at their bottom areas, e. the walls of the longitudinal slots having a rough, irregular surface configuration adapted to be scraped clean when the channel member is press-fitted into the slots.
 4. The invention as set forth in claim 3, wherein: a. the walls of the longitudinal slots have a ribbed configuration, constituting said irregular surface.
 5. A rail construction for rail-type electrification systems, comprising in combination: a. an elongate, electrically conducting rail constituted as a rigid metal extrusion of channel-like cross section provided with a pair of upstanding opposite, coextensive walls and a bottom connecting web, b. the upper edges of said walls having inwardly extending flanges, c. said connecting web having a pair of longitudinal slots opening at the bottom surface thereof, d. the opposite walls of said slots having irregular surfaces adapted to be scraped clean when the flanges of a channel member are pressed into the slots.
 6. The invention as defined in claim 5, wherein: a. the opposite walls of said slots have a ribbed configuration, constituting said irregular surfaces.
 7. A rail construction for rail-type electrification systems, comprising in combination: a. an elongate, electrically conducting rail having a pair of coextensive longitudinal slots substantially parallel to one another, b. an elongate, electrically conducting channel member having a pair of flange portions and a connecting web portion, said portions defining a generally U-shaped cross sectional configuration, c. said flange portions of the channel member being pressfitted into said slots so as to permanently retain the channel member on the rail, d. said slots having outer reentrant walls extending inwardly toward each other, whereby the slots are narrower at their mouth areas than at their bottom areas, e. the flange portions of the channel member each having thickened rims, f. each of the edges of the flange portions being turned back upon itself, the turned-back edges constituting the said thickened rims.
 8. A rail construction for rail-type electrification systems, comprising in combination: a. an elongate, electrically conducting rail having a pair or coextensive longitudinal slots substantially parallel to one another, b. an elongate, electrically conducting channel member having a pair of flange portions and a connecting web portion, said portions defining a generally U-shaped cross sectional configuration, c. said flange portions of the channel member being pressfitted into said slots so as to permanently retain the channel member on the rail, d. said slots having outer reentrant walls extending inwardly toward each other, whereby the slots are narrower at their mouth areas than at their bottom areas, e. said rail having a channel-like configuration, comprising a pair of upstanding, opposite, coextensive walls and a bottom connecting web, f. the upward edges of said walls having inwardly extending flanges, g. said slots being disposed in the bottom surface of said web. 